BACKGROUND To study the essential molecular mechanism of gall formation is very important. OBJECTIVE To investigate the differential gene expression in leaves fed on by Tetraneura akinire Sasaki and to provide a basis for the better understanding of the essential molecular mechanism of gall formation. METHODS The infected leaves of the elm were divided into three periods: initial formation period (T2), growth and differentiation period (T3), and cracking period (T4). The untouched leaves were used as the control (T1). RNA-Seq was performed, and the high-quality sequences were mapped to the reference genome and the elm gene database to obtain the gene expression profiles. The expression level of each gene was calculated by the RPKM method. A combination of FDR ≤ 0.01 and the absolute value of |log2 ratio (T/CK)| ≥ 2 was used as the threshold to determine the significance of gene expression. Finally, GO and pathway enrichment analyses were used to identify the significantly enriched functional classification and metabolic pathways in DEGs. RESULTS The results revealed that approximately 244 mRNAs were detected between T1 and T2, including 192 up-regulated and 52 down-regulated mRNAs; approximately 175 mRNAs were detected between T1 and T3, including 145 up-regulated and 30 down-regulated mRNAs; and approximately 372 mRNAs were detected between T1 and T4, including 360 up-regulated and 12 down-regulated mRNAs. Approximately 34 differentially expressed genes were identified by Venn analysis. Comparing the three infection periods to the control, there were 28 up-regulated and six down-regulated mRNAs. Additionally, 562 genes were used for cluster analysis, which revealed that the gene expression in T2 and T3 changed greatly. Genes related to cell proliferation and respiration, such as microtubulin and 6-phosphoric acid fructose kinase were mainly up-regulated during the T2 period. Genes encoding lipoxygenase, glutathione-S-transferase, superoxide dismutase and protease inhibitor were up-regulated during T2 and T3. Genes encoding lignocellulose synthase were up-regulated during T4, which suggests the reinforcement of the cell wall to improve the resistance to the damage of the Tetraneura akinire Sasaki. CONCLUSIONS The results showed that the feeding of Tetraneura akinire Sasaki caused the differential expression of elm genes and influenced cellular energy metabolism. These changes in physiological response and gene expression of the elm compose the physiological and molecular basis of the gall formation and may improve the resistance of elm to Tetraneura akinire Sasaki.

中文翻译：

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四叶草Sasaki饲喂榆树叶差异基因表达的研究。

背景技术研究胆汁形成的基本分子机制非常重要。目的研究四叶草（Satrasaki Tetraneura akinire Sasaki）摄食的叶片中的差异基因表达，为更好地理解胆汁形成的基本分子机制提供基础。方法将榆树的感染叶分为三个阶段：初始形成期（T2），生长和分化期（T3）和裂化期（T4）。未接触的叶子用作对照（T1）。进行RNA-Seq，并将高质量序列映射到参考基因组和榆树基因数据库，以获得基因表达谱。通过RPKM方法计算每个基因的表达水平。FDR≤0的组合。01和| log2比（T / CK）|的绝对值 ≥2作为确定基因表达显着性的阈值。最后，GO和途径富集分析用于确定DEG中显着丰富的功能分类和代谢途径。结果结果表明，在T1和T2之间检测到约244个mRNA，包括192个上调和52个下调。在T1和T3之间检测到大约175个mRNA，包括145个上调的mRNA和30个下调的mRNA；在T1和T4之间检测到约372个mRNA，包括360个上调和12个下调。通过维恩分析鉴定出大约34个差异表达的基因。比较三个感染时期与对照，有28个上调mRNA和6个下调mRNA。另外，使用562个基因进行聚类分析，结果表明T2和T3中的基因表达发生了很大变化。与细胞增殖和呼吸有关的基因，例如微管蛋白和6-磷酸果糖激酶，在T2期主要上调。在T2和T3期间，编码脂氧合酶，谷胱甘肽-S-转移酶，超氧化物歧化酶和蛋白酶抑制剂的基因被上调。编码木质纤维素合酶的基因在T4期间被上调，这表明细胞壁的增强可增强对四面膜动臂佐佐木（Tatraneura akinire Sasaki）损害的抵抗力。结论结果表明，四面膜拟佐佐木的摄食引起榆树基因的差异表达并影响细胞能量代谢。